I'm an optometric tech...I pretest patients and have learned a ton about the business from just being around it all day, and more importantly have realized I do indeed want to work in this field.
I basically got a pad of paper, went online, and wrote down the numbers/emails/etc for about 20-25 of the local clinics and just began calling people, letting them know I was a student just trying to get some experience. I asked if I could volunteer/shadow/work, really anything that was available. Most never responded or called me back. I interviewed for a tech job at one place which I didnt get because they wanted someone there long term, but eventualy I got a call and interview in a wonderful private practice and I am there all week now, learning all I can and getting the feel for one on one patient interactions, etc. It has helped me immensely and hope it will help my application immensely as well.
This is the advice I would give. Just call around...the first few I called I felt a bit dumb but by the 4th or 5th I had a routine i'd go through. Depending on the size of your city there should be a number of clinics, and often the job turnaround is high. The pay may not be great, but let them know that isnt your main intention. Good luck!